Dok Ruk Rim Tang and Taddao Bussaya both have the female lead pretending to be a boy to get into their dead father's house to try and get information. I've only seen the beginning of Dok Ruk Rim Tang, and she's there to try to find out how her father died I don't know if she suspects the male lead specifically.
In Plerng Naree and Fai Lang Fai they both infiltrate the companies the male lead is connected with, and the male leads suspect them, but they have no proof that they are up to no good, which is a bit like Paen Rai Long Tai Wa Rak.
There's also something like Mask, which she's taking the place of someone who's already died and she's isolated and doesn't know if she can trust the male lead.